Jan 14, 2020 Update
Cast is off! I'm all done with casts.
Visited the surgeon to confirm appropriate progress and get the cast removed. X-rays look very good. The tibia has been pulled together into a single bone again and is healing nicely. Fibula is still cracked, which can be seen in the x-ray, but that will heal on its own. Great hardware holding everything together—primarily a rod (medical term a "nail") inside the tibia and a plate along the side, which pulls the pieces together near the bone's end.
They cut the cast off and replaced it with a removable boot. I wear it when out and about but nearly always removed when inside. Starting to feel more human again.
Still eight weeks to go before I can put any load on the leg, but now I can (1.) remove the boot when not out in public (which I do all the time!), (2.) move the ankle to regain flexibility, (3.) take a shower or bath without covering anything, and (4.) sleep comfortably with nothing on my leg. In a few days I'll be able to submerge the leg in a tub or spa.
Fantastic progress! Feels good. Time to get to work on regaining joint motion in the foot and ankle. Maybe even build a bit of muscle back in my chicken thin leg.